The invention is based on a reciprocating piston pump as defined hereinafter.
A pump of this kind is already known (British Patent 484,142), in which a roller bearing ring has a disk with an end face which is engaged by a plurality of pump pistons having a longitudinal axis that extends parallel to the longitudinal axis of a drive shaft. Such a pump is known as a swash plate pump and is classified as a reciprocating piston pump; in such a pump, the pumping flow of an individual cylinder has an approximately sinusoidal course, with an intake phase and a pumping phase of equal length. This supply flow course makes reciprocating piston pumps loud when in operation. This is due to changes in the pressure acting upon the pressure-impinged pump components and to changes in force in the pump drive train, which incite the pump housing to vibrate and make noise. Moreover, components such as valves, lines, and control motors through which the operating fluid of the pump flows also contribute to noise emissions, because of the pulsating flow of fluid. The noise level depends on the magnitude of the changes in pressure and force and on the speed with which they take place. As mentioned, pumps with only one cylinder are especially unfavorable in terms of these variables that affect loudness, because they pump only during half of one cycle, which is made up of an intake stroke and a compression stroke (that is, the intake phase and the pumping phase), and so the pumping flow varies between zero and a maximum. The speed of the change in force in the drive mechanism (drive train) and the pressure pulsation of the pumping flow are correspondingly high as well.